“Ultraviolet radiation is the major environmental insult to the skin and stimulates the synthesis of melanin in melanocytes, which then distribute it to the neighboring keratinocytes where it confers photo-protection. Skin color results from the paracrine interaction between these two cell types. Recent studies suggest that endocannabinoids are potential mediators in the skin. Here, we investigated whether cannabinoid drugs play a role in melanogenesis and if ultraviolet radiation modifies the cutaneous endocannabinoid system.
We provide evidence that human melanoma cells (SK-mel-1) express CB(1) receptors…
Furthermore, ultraviolet-B radiation increased endocannabinoids levels only in keratinocytes, whereas CB(1) cannabinoid receptor expression was up-regulated only in melanoma cells.
Our results collectively suggest that ultraviolet radiation activates paracrine CB(1)-mediated endocannabinoid signaling to negatively regulate melanin synthesis.
The endocannabinoid system in the skin may be a possible target for future therapies in pigmentary disorders.”